I honestly don't have a problem with this. Hollywood is big business, and one flop can spell the end of your career (and as far as our community should be concerned, this movie needs to do well). Eddie Redmayne is a fantastic actor and a safe choice. I would also like to see this movie done well and with masterful performances. If this film could gain a huge audience and change some hearts and minds about what it's like to be transgender, then it's really a win for everyone. I would imagine that most A-list actors in Hollywood would give their proverbial left nut for a transgender role these days, as it's a hot topic and is a great vehicle to land yourself some Oscar buzz. If a trans actress auditioned for such a role, there would be some very stiff competition.
Of course I would love to see a trans actress in that role, but there frankly aren't many (yet) that are household names. (Seriously, name someone other than Laverne Cox.) What I fear is that before there are some real breakout trans actors to land these roles, there will likely need to be a glut of low-budget transploitation films, not unlike "Ticked off Trannies With Knives" and/or the second coming of Ed Wood.
Having a forthcoming major motion picture that sheds positive light upon our community is still progress, and I will happily take it.